Sunspots appear dark because they are what ?

The correct term for the total amount of living tissue within a given trophic level is biomass. It encompasses the weight of all living organisms within an ecosystem or a specific trophic level. The answer to the student's query is thus d. biomass.

The total amount of living tissue within a given trophic level is referred to as the biomass. Biomass can be considered as the weight of all living organisms within a particular ecosystem or at a specific trophic level. This includes animals, plants, microorganisms and all other living things. For example, in a forest ecosystem, the biomass includes everything from the massive trees to the tiny fungi and bacteria within the soil. Therefore, the answer to the student's question is d. biomass.

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Final answer:

In the oxidation half-reaction, every mole of Mg(s) loses 2 moles of electrons. Therefore, to balance the 2.0 moles of electrons gained by [tex]Ni^2^+[/tex](aq), 2.0 moles of Mg(s) must have lost 2.0 moles of electrons.

Explanation:

The question involves determining the number of moles of electrons lost by Mg(s) during a redox reaction where electrons are transferred from magnesium to nickel ions.

The given balanced reaction is oxidation of Mg(s), which can be represented as: Mg(s) → [tex]Mg^2^+[/tex](aq) + 2e-. Every mole of Mg loses 2 moles of electrons during the oxidation process.

If 2.0 moles of electrons are gained by [tex]Ni^2^+[/tex](aq), this corresponds to the reduction half of the reaction, and the same number of moles of electrons must have been lost by Mg in the oxidation half. Hence, 2.0 moles of Mg would lose 2.0 moles of electrons to provide the electrons gained by [tex]Ni^2^+[/tex](aq).

The net ionic equation for the reaction between aqueous nitric acid and aqueous sodium hydroxide is H+ (aq) + OH- (aq) → H2O (l). It represents a neutralization reaction, where hydrogen ions from the nitric acid and hydroxide ions from sodium hydroxide react to form water.

The net ionic equation for the reaction between aqueous nitric acid (HNO3) and aqueous sodium hydroxide (NaOH) is an example of a neutralization reaction, where an acid and a base react to form water and a salt. The general complete ionic equation would be: HNO3(aq) + NaOH(aq) → NaNO3(aq) + H2O(l). However, to obtain the net ionic equation, you only include the species that undergo a chemical change, which are the hydrogen ions (H+) from the nitric acid and the hydroxide ions (OH-) from the sodium hydroxide. Thus, the net ionic equation becomes: H+ (aq) + OH- (aq) → H2O (l).

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Final answer:

The bond angle in ozone is not exactly 120° due to electron pair repulsion and resonance structures, which cause deviations from the expected angle as explained by valence bond theory and hybridization.

Explanation:

The o-to-o-to-o bond angle in an ozone (O3) molecule is not exactly 120° because of the effects of electron pair repulsion and the molecule's resonance structure. Unlike a perfect equilateral triangle where angles are 120° due to identical bonding situations, in ozone, there are lone electron pairs on the central oxygen atom that push against the bonding pairs, causing a deviation from the expected angle. Additionally, the resonance structures contribute to an unequal distribution of electron density, further altering the bond angles.

Valence bond theory and hybridization explain that bonding in such molecules deviates from simple p-orbital overlap that would predict a 120° angle. Instead, these molecules adopt shapes that minimize the repulsion between electron pairs, which in case of water, leads to a bond angle of 104.5°, despite predictions of a 90° angle from unhybridized p-orbitals.

Answer: Both will diffuse at the same rate

Explanation:

According to Graham's law, the rate of diffusion is inversely proportional to the square root of the relative molecular mass of the gases. The two gases, carbon II oxide and nitrogen gas has the same relative molecular mass (28). This implies that they must diffuse at the same rate through an membrane.

Answer:

d

Explanation:

Final answer:

To find the number of moles of neon in 14.3 L at STP, divide the volume by the molar volume of 22.4 L. The result is 0.638 moles of neon.

Explanation:

To determine the number of moles of neon that occupy a volume of 14.3 L at STP (standard temperature and pressure), you use the concept of molar volume. At STP, a mole of any gas occupies 22.4 L. Therefore, you can calculate the moles of neon using the volume and the molar volume as a conversion factor.

The formula for this calculation is:

Moles of neon = Volume of neon (L) / Molar volume (L/mol)

So as an equation:

Moles of neon = 14.3 L / 22.4 L/mol

This gives us:

Moles of neon = 0.638 moles

This is a conversion between moles and gas volume at STP and is a fundamental principle in chemistry.

Final answer:

The molality of a glucose solution with 257 g of glucose dissolved in 1.62 L of water is 0.880 mol/kg. This is determined by converting the mass of glucose to moles and then dividing by the mass of the water in kilograms.

Explanation:

To calculate the molality of the glucose solution, we need to know the amount of solute (glucose) in moles and the mass of the solvent (water) in kilograms. The molecular weight of glucose (C6H12O6) is 180.16 g/mol.

First, convert the mass of glucose to moles:

(257 g glucose) / (180.16 g/mol) = 1.426 mol glucose

Next, since the density of water is assumed to be 1.00 g/mL, we use that to find the mass of the water:

(1.62 L water) (1000 mL/L) (1.00 g/mL) = 1620 g water = 1.62 kg water

Now, we can calculate the molality (m):

m = mol solute / kg solvent = 1.426 mol / 1.62 kg = 0.880 mol/kg

The molality of the glucose solution is 0.880 mol/kg.

Answer:

I think the answer is Protons.

Protons are the positive subatomic particles in an atom. They reside in the nucleus of the atom and their number determines the type of the element. Normally, atoms maintain a balance of protons and electrons, resulting in a neutral overall charge.

In an atom, the positive subatomic particles are called protons. These particles are located in the nucleus, or center, of the atom. Protons are one of three main subatomic particles in an atom, along with neutrons (which have no charge) and electrons (which have a negative charge).

The number of protons in an atom's nucleus determines the type of element it is. For example, an atom with 1 proton is hydrogen, an atom with 6 protons is carbon, and so on. The balance of protons and electrons in an atom determines the atom's overall charge. Normally, atoms have an equal number of protons and electrons, so their charges balance out, resulting in a neutral charge overall.

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Answer:

Gravity helped to hold things in orbit and create the planets.

Explanation:

Scientist believe that the solar system started in a similar way to stars, from a nebula. They say that the it was a cloud of dust and gas called a nebula that contained mostly hydrogen and helium leftover from the "Big Bang"(which I have my arguments about.) They also say there were heavier elements. Gravity caused the nebula to shrink. As the nebula became smaller it had a rotation. As it got smaller it began to spin faster. The planets were formed by materials cooling off. As they were cooling off they began to clump together. Clumps collided with each other to make a bigger clump. Larger clumps would attract smaller clumps with their gravitational pull. Eventually the clumps started to form the planets and moons in today's solar system.

Answer: it decreases the activation energy for a chemical reaction.

Explanation:

Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and convert to products.

The catalyst itself does not take part in the chemical reaction and is regenerated as such at the end.

A catalyst plays a key role in reducing the activation energy for a chemical reaction by providing an alternative reaction pathway that requires less energy. Because of this reduction in energy, the reaction can proceed more rapidly. The catalyst itself is not consumed in the reaction and can be used again.

A catalyst works by providing an alternative reaction pathway that requires less energy, thus decreasing the activation energy for a chemical reaction. In other words, it helps to speed up the reaction by lowering the energy needed for it to occur.

Let's take the example of a hypothetical reaction, 'A + B → AB'. Without a catalyst, this reaction might require a high activation energy, prohibiting the reaction from occurring under typical circumstances. However, with a catalyst, the reaction might proceed with an intermediate step 'A+C → AC → AB + C'. In this example, 'C' is the catalyst and 'AC' is the intermediate step; each individual step needs less energy than the original reaction, thus lowering the overall activation energy.

It's important to note that catalysts do not change the total energy of the reactants or the product; they just make it quicker for the reaction to reach the product stage. After the reaction, the catalyst is not consumed and can be used again for the same reaction.

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Answer:

It must be vaporized is the answer

Explanation:

took thest

Answer:

This is a specific type of dipole-dipole force is known as Hydrogen bonding.

Explanation:

Hydrogen bonding (H-bonding) is an intermolecular force having partial ionic-covalent character. H-bonding takes place between a hydrogen atom attached with an electronegative atom( like : O, N and F) and lone pairs of electrons on an neighboring atoms.

Generally this type of bonding is observed where atoms like nitrogen , oxygen, fluorine attached to another molecule are present in neighbors of a hydrogen atom attached to other molecule. This bonding arises due to the interaction between the  developed partial positive and negative charges on the hydrogen and electronegative atoms.

Answer:  Engineers can design better bridges because they know how metal changes shape.

Explanation:  Physical Properties are those properties which are also regarded as observable because they can be easily seen or observe through naked eyes like melting point etc.

These are those properties which do not change chemical identity of the species.

Thus out of the given options, only physical property is the change of shape of metal.

And the rest one represents the chemical property as chemical property are the one which changes the chemical identity of the substance.

According to law of conservation of mass, mass is neither created nor destroyed and hence for a chemical reaction the mass of reactants and products is equal.

According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.

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Answer:

Alcoholic fermentation

Explanation:

Alcoholic fermentation is an anaerobic process executed by yeasts, molds and some bacteria, which cause chemical changes in organic substances.

Alcoholic fermentation has the biological function of supplying energy to microorganisms in the absence of oxygen. To achieve this, the glucose molecules are dissociated and in this way the energy required to survive is obtained, producing ethanol and CO2 as products.

According to the Arrhenius theory a substance that yields hydrogen ions as the only ion in an aqueous solution is Acid.

Acids are those substances which are having pH range from 0 to 7.

According to the Arrhenius theory of acid and base, acids are those compounds which donate H⁺ ion or proton in the aqueous medium and bases are those substances which donate OH⁻ ion in the aqueous medium.

Example of Arrhenius acids are HCl, CH₃COOH, HNO₃, etc.

Hence, those substance which yields H⁺ ions is acids.

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Answer: The oxidizing agent for the given reaction is Silver.

Explanation:

Oxidizing agent is defined as the agent which helps the other substance to get oxidized and itself gets reduced. It undergoes reduction reaction in which a substance gains electrons. The oxidation state of this substance gets reduced and the substance gets reduced.

Reducing agent is defined as the agent which helps the other substance to get reduced and itself gets oxidized. It undergoes oxidation reaction in which a substance looses its electrons. The oxidation state of this substance gets increased and the substance gets oxidized.

For the given chemical reaction:

[tex]Pb+2Ag^+\rightarrow Pb^{2+}+2Ag[/tex]

The half reactions for the given above chemical reaction is:

Oxidation half reaction:  [tex]Pb\rightarrow Pb^{2+}+2e^-[/tex]

Reduction half reaction: [tex]2Ag^++2e^-\rightarrow 2Ag[/tex]

As, lead is loosing electrons. So, it is getting oxidized and is considered as a reducing agent and silver is gaining electrons. So, it is getting reduced and is considered as an oxidizing agent.

Thus, the correct answer is silver.

Answer:

56 g

Explanation: